1. Field of Invention.
This invention relates to a shipping pallet made of metallic material and which in addition to providing a flat surface for large drum containers, provides a secondary containment for hazardous materials that may leak from the large primary containers.
2. Prior art.
The most common shipping pallets are made of wood but wooden pallets suffer from many faults, not the least of is the fact that wooden pallets have a limited lifetime, lasting for only two or three trips, and additionally suffer from weather degradation and do not function as a secondary container.
Various designs and construction types for shipping pallets have been patented. For example, Griffin U.S. Pat. No. 4,000,704 fabricated a nestable molded pallet and container providing interlocking and stacking capabilities. Wind U.S. Pat. No. Re. 32,344 provides for a shipping pallet formed from a unitary sheet of formable material and which allows the user to form a shipping container by attaching a protective sleeving and restraining with a plurality of strapping bands. However, despite a number of prior art designs for pallets functioning as a container, the problem of secondary containment of hazardous materials has not been addressed. Further, The Department of Transportation merely requires that the "shipping containers shall not leak" and "shall be tied down." Since the primary containers presumably do not leak and the containers can be tied to the wooden pallets, hazardous materials containers continue to be shipped on prior art wooden pallets despite their limited lifetime and lack of any secondary containment.
A prior art wooden pallet is substantially square and has an open lattice like flat surface. The wooden pallets are not designed to provide a secondary containment against hazardous material spillage. For example, if a standard 55-gallon drum leaks, the spilled material flows through the upper surface of the pallet, through to the supporting surface which may be the ground surface or the inside of a transport carrier. If the hazardous material seeps into the ground surface, the risk of environmental damages increases. It is well settled that once hazardous material seeps beyond the surface and into the aquifer layer, costly and lengthy reclamation of the contaminated ground is mandated. This problem of hazardous material leakage and clean-up can be further hampered by a delayed discovery of the leakage. When a pallet of 55-gallon drums is transported in a transit carrier such as a tractor-trailer, a leakage of hazardous material may be hidden until the drums are removed from the carrier and delivered to their destination. While hazardous material spillage within the transit carrier requires costly safety and clean-up measures, the problems resulting from the spillage leaking beyond the transit carrier and into the environment escalate the problems.
Many times, the problems of hazardous material transport is amplified by man made conditions. For example, transit drums (55-gallon containers) are loaded into a transit carrier and placed on a railroad car or even directly loaded into the railroad car. Once the railroad cars are loaded, they may be sidetracked enroute to their final destination. These uncooled and unventilated containers may remain in switching yards or sidetracks for weeks at a time. Elevated temperatures may contribute to a rupture in the manufacturers containers, thus allowing hazardous materials to seep out of the container car and then into the ground surface.
If the leakage occurs in a cross country transit the problem is also enhanced, as the carrier travels from departure point to destination the hazardous material leakage may be continually contaminating the ground surface. Therefore, rather than dealing with a localized spill, clean up is now a long distance process. From all aspects, clean up is costly, both in environmental effects as well as monetary effects, and is time consuming. Liability for hazardous spills and clean up can be attributed to the shipper, the drum manufacturer, the chemical manufacturer, etc., thus enhancing liability in addition to damaging the environmental surroundings.
Accordingly, effort has been directed to designing a reusable shipping pallet which functions as a stable shipping or storage platform and provides effective secondary containment.